You can link to a video just as you would link to anything else. You can link text, buttons, and images.
Video cannot be embedded like you would on a website, because it will not work in most email clients and will get stripped out, however, a good alternative is to take an image, usually a screenshot of the video with a play button over it, and then link that image to the video or to a webpage that has the video.
For example, to create a image for your video that you use in email:
- Upload your video to YouTube
- Go to the share options and select embed
- Grab the URL portion of the embed code only and paste it into a new browser tab. your video will be the only thing on the page. You will also use this URL in the mail to link the image to the video.
- Use CTRL + to zoom in on the video, which also makes the red YouTube play button larger
- Screenshot that and use it as your image to insert into your email and link to your video.
Another option, if your video is short (less than 5 sec) you can create an animated gif of the video and use that in your email. You could then also link this animated gif to a webpage that has the full video.